1. Technical Field
The present invention relates to a liquid ejecting head capable of ejecting liquid droplets from nozzles and a method of inspecting the liquid ejecting head, and more particularly, to an ink jet printing head capable of ejecting ink droplets and a method of inspecting the ink jet printing head.
2. Related Art
A representative example of a liquid ejecting head is an ink jet printing head which includes a plurality of pressure generating chambers communicating with nozzles ejecting ink droplets and a reservoir communicating with the plurality of pressure generating chambers. In the ink jet printing head, ink supplied from the reservoir to the pressure generating chambers is pressurized by pressure generating units such as piezoelectric elements to eject ink droplets from the nozzles. For example, there was suggested an ink jet printing head which includes a plurality of pressure generating chambers, ink supply passages respectively communicating with the plurality of pressure generating chambers, a passage forming board including communication portions respectively communicating with the pressure generating chamber via the ink supply passage, piezoelectric elements formed on one surface of the passage forming board via a vibration plate, and a protective board including a piezoelectric element retaining section joined to the passage forming board and protecting the piezoelectric elements. In this ink jet printing head, a reservoir portion forming a reservoir along with the communication portions is formed through the protective board.
In the ink jet printing head with such a configuration, a breakage may occur from vibration during the manufacturing process. For example, since the linear expansion coefficient of the passage forming board is different from that of the nozzle plate in which the nozzles are punched, the passage forming board may be bent and thus a breakage may occur in the vibration plate.
For this reason, an inspecting process of inspecting whether a breakage occurs in the vibration plate is performed when the product is completed. When the nozzle plate is formed of a conductive material, it can be relatively simply inspected whether a breakage occurs in the vibration plate by detecting a conductive state between the nozzle plate, a lower electrode film, a first independent electrode layer, and a second independent electrode layer in a state where a liquid such as ink fills from the reservoir to the pressure generating chambers (for example, see JP-A-2008-221652).
When the nozzle plate is formed of a conductive material, as described above, a breakage in the vibration plate can be inspected by detecting the conductive state between the nozzle plate and the lower electrode film. However, when the nozzle plate is formed of an insulating material, a problem may arise in that this inspecting process may not be used and a breakage in the vibration plate may not be detected easily.
This problem may arise not only in the ink jet printing head but also in a liquid ejecting head ejecting a liquid other than ink.